Traditional methods of testing for diseases, drugs and other antigens in humans have up until the last few years been predominantly done using blood samples. These samples collected in laboratories at the request of physicians require that blood drawn by a trained phlebotomist is sent to a laboratory and the serum component comprising a predominance of immunoglobulins, containing antibodies to the disease or disease state in question, is tested using a variety of available test kits to assist in the diagnosis of various diseases including infectious diseases, cardiovascular diseases, cancers and many others. Such samples can also be tested for the presence of non-disease analytes such as metals, minerals, DNA, bacteria and organic molecules among others.
Under current standardized laboratory practices, it is necessary to confirm any initially positive result obtained from diagnostic or analytical testing with a more sensitive (accurate) method. This, in fact is true for most, if not all diagnostic tests used today, including, as an example, HIV tests, which are confirmed by more definitive methods such as Western blot techniques or immunofluorescence (IFA) assays. In the case of drug tests, for instance, performed in criminal justice settings (at the police car, in correctional facilities, in drug courts, etc.) or at the workplace, by way of two examples, confirmation is carried out using gas chromatography-mass spectrometry (GC-MS), gas chromatography-mass spectrometry-mass-spectrometry (GC-MS-MS) or liquid chromatography-mass spectrometry-mass spectrometry (LC-MS-MS) on a second sample taken from the subject. Other diagnostic and screening methods require similarly accurate methods for confirmatory purposes.
The United States Substance Abuse Mental Health Services Administration (SAMHSA), the designated body responsible for regulating Federal drug testing in the United States, has recently prepared guidelines for the introduction of new tests and sample collection procedures for drug tests using so-called, “alternate” specimens. These sample types include saliva (or oral fluids), hair and sweat. These guidelines define the need for (1) a confirmatory specimen to be collected at the time of the initial sampling, (2) defined specimen volumes to be collected and (3) expected drug cut-off values, among other requirements.
The need for duplicate, or a multiplicity of mutually distinct samples taken from the same source at the same time is part of a general trend being observed in many areas of the diagnostic and analytical testing businesses. The main reason for this increasingly important trend is the legal implication of being able to definitively rule out any potential contamination of the test sample during the testing process. The obvious consequences of an incorrect diagnosis of HIV for a patient or erroneous DNA results in the case of a criminal case are just two examples of where 100% certainty of sample integrity are paramount and are contributing reasons for the development of this particular invention. This potential legal implication has had an impact on general testing protocols and as a result healthcare and other professionals are now more cognizant than ever of the need to collect a “pure” sample or samples then ensure that those samples are analyzed to produce accurate results. During the testing process absolute “chain-of-custody” rules are enforced to ensure that no adulteration or contamination of the specimen occurs. This is not always possible in current testing protocols as there are opportunities for sample contamination or sample tampering. This is true for any test whether done on blood, serum, saliva, nasal secretions, vaginal discharge or any other sample where information obtained relates to a diagnosis of disease or disease state. Such information is taken in conjunction with any additional information available to the person making a decision relating to interpretation of the results obtained.
Despite the fact that saliva has been used as a diagnostic fluid since Ancient Chinese times, when the “Rice Test” (which relied on the inhibition of saliva as a determinate of guilt) was used, it is only over the last few years that salivary testing has taken on much greater significance. There are several important factors, which have contributed to this change: (1) The increase in popularity of non- or less-invasive testing methods; (2) the availability of more sensitive antibodies and antigens for detection of immunoglobulins in saliva; (3) new technologies in the area of point-of-care testing; (4) a need for more rapid results; (5) acquisition of serum/blood involves patient discomfort and can cause difficulty particularly where young children or intravenous drug users are concerned; (6) use of venous blood to collect serum requires capital equipment and involves an initial processing step, which adds significant time to result turnaround and has additional cost implications and also; (7) a general movement away from centralized laboratory testing towards “near-patient” testing, also called “point-of-care” testing.
The National Institutes of Health (NIH) recognized the value of salivary testing as early as 1993 and recent symposia orchestrated by this organization, for instance a meeting held in 1999, organized by NIH's National Institute of Dental and Craniofacial Research (NIDCR) division has helped increase the profile of testing using oral fluids. NIH, through various divisions, has since been encouraging companies with expertise in this area to apply for funding for new projects aimed at introducing novel tests using non-invasive samples for laboratory and point-of-care applications.
The insurance testing industry uses saliva as a sample matrix for applicants wishing to purchase specific life insurance policies as a safeguard measure prior to writing policies. In these situations applicants are tested for HIV, cotinine (nicotine) and cocaine using a testing device called “OraSure” from OraSure Technologies, which collects oral fluids for subsequent testing under laboratory conditions. Each of the major insurance testing laboratories in the United States performs a significant number of oral fluid tests on an annual basis.
In April 2004 OraSure Technologies was successful in gaining FDA approval for its OraQuick® HIV 1/2 rapid test for oral fluid diagnosis of the HIV viruses type 1 and type 2. Previously the test had been approved by the agency for whole blood, serum and plasma only.
In a separate area drugs of abuse are routinely detected from oral fluids collected in the workplace, in criminal justice settings and in hospitals using OraSure Technologies' “Intercept™” device and associated range of ELISA microplate assays. In this case a panel of 5 “abused” drugs or more are measured under laboratory conditions.
Rapid testing devices using saliva have recently appeared, which may be used at the “point-of-care”. These devices can collect and perform immediate testing for several drugs of abuse but these suffer from poor performance for certain tests at the present time, particularly Tetrahydrocannabinol (THC) or its major metabolite 11-nor-Δ9-Tetrahydrocannabinol. Examples of this type of device are the OraTect™ test from Branan Medical Corporation, the OraLine assay from Sun Biomedical and the Cozart BioScience RapiScan device, among others.
Up until now urine based rapid drug testing has been performed preferentially due to availability, cost, and to a certain extent, a lack of salivary tools incorporating some of the features described in this invention. While rapid urine kits are widespread they suffer from issues related to “chain-of-custody”, the need for facilities to collect urine specimens discreetly under appropriate supervision and are easily adulterated by knowledgeable users, who can “cheat” such tests.
Electronic reading, hand-held devices, such as the Cozart BioSciences RapiScan instrument are also now available outside of the United States, that allow immediate drug testing to be done from oral fluids at the roadside and other field settings. This technology requires sample collection from the donor then immediate testing on site. This concept may well be duplicated in the future, as technologies to “miniaturize” testing platforms, improves.
The FDA has approved a laboratory HIV test, OraSure HIV-1 for testing for the HIV-1 virus from oral fluid as well as a Western blot confirmatory test, which also uses oral fluids. Both have been used in a Public Health setting in the United States for over five (5) years.
In addition the FDA has also approved saliva tests for pre-term labor (SalEst™, salivary estriol, from Biex, Inc), a salivary alcohol test (QED®, OraSure Technologies), a cortisol assay (Salimetrics, Inc.) as well as a panel of saliva-based drug assays (Intercept, OraSure Technologies) through the 510(k) clearance system. A number of other oral fluid drug testing products are undergoing regulatory approval, so in the next 12-24 months we might expect to see several other products available in the U.S. Furthermore, “investigational use” tests are available for immunoglobulins, for example sigA (for use in psychological disorders, stress and athletic performance), therapeutic drugs (for instance lithium, theophylline, AZT), tumor markers (e.g. Her-2/neu), bacterial antibodies such as helicobacter pylori and even genomic detection of mitochondrial DNA (for criminal justice applications) using oral fluids as the preferred specimen matrix.
Emerging methodologies based on microfluidic technology requiring only small quantities of specimen samples are approaching the market. These devices work on virtually any specimen matrix including, but not limited to, saliva, urine, whole blood, serum, and other fluids. Such techniques have already found use in the arena of biodefense monitoring, high throughput screening methods, high performance liquid chromatography (HPLC) and other analytical techniques. These devices, which are being developed in one particular area for use by special intelligence forces, who are required to test for chemical and biological agents in soil, water and other samples before troops arrive at a battle site or during peacekeeping to monitor biological or environmental samples, may be seen as another area where this invention will find application.
These are a few of the many instances where saliva is viewed as a viable sample matrix for testing purposes. A number of devices in use today have provided means for the collection of bodily fluids including saliva and urine among others. One FDA-cleared fluid collection device used predominantly for saliva collection and testing has been shown to be potentially unsafe in pediatric patients. The Saliva•Sampler™ device from SDS, Inc. utilizes perforations present on filter paper to facilitate removal of the filter paper for subsequent saliva separation and testing. The device is placed under the tongue to accumulate sublingual whole saliva, collected by leaving the sampling device, consisting of a filter paper material attached to a plastic stem, in position until a sample indicator built into the device changes color confirming sample sufficiency. The process requires that the subject not chew, bite or unnecessarily move the device during the collection procedure. In pediatric patients, particularly, this can be a problem as children have a tendency to chew on materials placed in the oral cavity. In infants, separation of the filter paper prematurely can result in choking.
In another previously described example, an alternate FDA-approved oral fluidcollection system from OraSure Technologies, Inc., known as OraSure®, incorporates salts impregnated on to the collection medium in the form of a “hypertonic” solution. According to the manufacturers, the purpose of the salts is to facilitate ready absorption of oral fluids (oral mucosal transudate) from the gingival crevices and thereby reduce sampling time. In practice when the OraSure® device is placed in the oral cavity, the taste of the salts on the device medium may be distasteful to potential users.
These and other currently available devices fail to address a growing need for efficient collection of bodily fluids including saliva for applications including analytical or diagnostic testing under laboratory, field or point-of-care testing conditions, for instance, whereby a pure sample of fluid, for example saliva, is collected from a subject and split into multiple chambers, thereby providing a means for initial specimen testing analysis or storage, for confirmation or supplementary testing and simultaneously providing a mechanism for confirming sample sufficiency prior to any subsequent testing or analysis of the constituents of the bodily fluid so collected.
Lateral flow immunochromatography (ICT) tests have been around for over a decade and are a direct descendent of thin-layer chromatography (TLC) techniques pioneered during the 1970s. The technology offers some benefits including cost efficiencies, user-friendliness and the availability of immediate test results. Over the last decade in particular, the availability of high quality raw material components, the growing movement towards near patient or point-of-care (“POC”) testing, coupled with a need for rapid results, has led to an “explosion” in the development and commercialization of both flow-through and lateral flow devices based on immunochromatographic test principles. These devices form part of a rapidly growing industry for diagnostic tests performed outside of the laboratory.
A variety of ICT tests are now available including as examples OraSure Technologies' rapid oral fluid test, OraQuick HIV 1/2, Quidel Corporation's Quick-Vue Streptococcus A and Helicobacter pylori rapid tests, Meridian BioSciences' ImmunoCard assays for Respiratory Syncticial Virus (RSV) and Clostridium Difficile (C. Difficile) and Roche Diagnostics' TestCup drugs of abuse tests among a multitude of others.
Technologies other than ICT are equally adaptable to rapid testing. These include latex agglutination, dot-blot tests, microarrays and others.
Of the above rapid test examples and those currently in existence, only OraSure Technologies has been successful in commercializing a rapid, oral fluid test, OraQuick HIV 1/2, despite the fact that oral fluid, point-of-care tests represent an attractive alternative to current testing methodologies. This may be due, in part, to current data requirements for approval of rapid tests in the U.S. This is expected to change as a result of OraSure's success with OraQuick® HIV 1/2 and the emergence of saliva-based drug testing assays.
In order to meet the needs of a growing Public Health demand in the U.S. it is important for would-be manufacturers to integrate test strip technologies similar to those mentioned above with a simple-to-use, integrated platform system that can deliver rapid test results, safely and cost-effectively, for a range of diseases or analytes in a non-invasive manner. This is especially important in view of Centers for Disease Control (CDC) estimates that suggest that, of 2.1 million people tested at Publicly-funded Government testing sites using traditional (laboratory) testing methods in the US for the HIV virus, approximately 33% do not return to receive their results and may unwittingly go on to infect others if they are in fact HIV-positive. As the key to all disease prevention is early detection, accurate and early detection using rapid tests can have a major impact on reducing disease incidence.
In needle-averse populations, for instance, small children, pregnant women and hemophiliacs, the opportunity to provide oral fluid or saliva collection and immediate testing as an alternative to blood-based systems would be welcomed. Similarly general practitioners and health professionals would see an opportunity to provide testing opportunities in non-traditional testing sites, such as in the privacy of the patient's home, in nursing homes, remote clinic settings and even over the counter in a pharmacy environment.
Cozart BioSciences (UK, www.Cozart.co.uk)) has described the use of a hand-held device known as RapiScan, which tests for several illicit drug entities from oral fluids. This reading system is not fully integrated and requires a separate collection step prior to testing the specimen. OraSure Technologies (www.OraSure.com) has also described in a recent U.S. patent application (application No. XXXX), the use of a sample collector and test device. In this example also, sample collection is distinct from the specimen testing process.
SAMHSA has proposed in its 2004 guidelines for alternate specimen testing that minimum oral fluid collection volumes are to be 2 mL of clean specimen.
None of the available prior art provides for expressing an oral fluid sample from a subject directly onto a diagnostic test strip, providing a mechanism for determining sample volume adequacy and visually reading qualitative and/or quantitative results from the test strip through a small window in an integrated one-step manner.
The following represents a list of known related art U.S. Pat. No. 5,283,038 issued Feb. 1, 1994, U.S. Pat. No. 5,260,031 issued Nov. 9, 1993, U.S. Pat. No. 5,268,148 issued Dec. 7, 1993, U.S. Pat. No. 5,393,496 issued Feb. 23, 1995, U.S. Pat. No. 5,380,492 issued Jan. 10, 1995, U.S. Pat. No. 5,376,337 issued Dec. 27, 1994, U.S. Pat. No. 6,267,722, U.S. Pat. No. 6,027,943, U.S. Pat. No. 6,187,598, U.S. Pat. No. 5,965,453, U.S. Pat. No. 5,393,496, U.S. Pat. No. 4,943,522, U.S. Pat. No. 4,895,808, U.S. Pat. No. 6,372,516, U.S. Pat. No. 6,046,058, U.S. Pat. No. 5,962,336, U.S. Pat. No. 5,238,652, U.S. patent application Ser. No. 10/061036 by Lloyd Simonson, U.S. patent application Ser. No. 10/060605 by Lloyd Simonson, U.S. Pat. No. 6,627,152, U.S. Pat. No. 6,727,879, U.S. Pat. No. 5,922,614 to Edward Cesarczyk, U.S. Pat. No. 6,489,172. The teachings of each of the above-listed citations (which does not itself incorporate essential material by reference) are herein incorporated by reference. None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed.